Influence of Burning-Induced Electrical Signals on Photosynthesis in Pea Can Be Modified by Soil Water Shortage

Abstract

Local damage to plants can induce fast systemic physiological changes through generation and propagation of electrical signals. It is known that electrical signals influence numerous physiological processes including photosynthesis; an increased plant tolerance to actions of stressors is a result of these changes. It is probable that parameters of electrical signals and fast physiological changes induced by these signals can be modified by the long-term actions of stressors; however, this question has been little investigated. Our work was devoted to the investigation of the parameters of burning-induced electrical signals and their influence on photosynthesis under soil water shortage in pea seedlings. We showed that soil water shortage decreased the amplitudes of the burning-induced depolarization signals (variation potential) and the magnitudes of photosynthetic inactivation (decreasing photosynthetic CO2 assimilation and linear electron flow and increasing non-photochemical quenching of the chlorophyll fluorescence and cyclic electron flow around photosystem I) caused by these signals. Moreover, burning-induced hyperpolarization signals (maybe, system potentials) and increased photosynthetic CO2 assimilation could be observed under strong water shortage. It was shown that the electrical signal-induced increase of the leaf stomatal conductance was a potential mechanism for the burning-induced activation of photosynthetic CO2 assimilation under strong water shortage; this mechanism was not crucial for photosynthetic response under control conditions or weak water shortage. Thus, our results show that soil water shortage can strongly modify damage-induced electrical signals and fast physiological responses induced by these signals.

Integration of Electrical Signals and Phytohormones in the Control of Systemic Response

“…In most cases, the formation of a systemic response to local stimuli occurs within minutes and hours, such as changes in the activity of photosynthesis, transpiration, the level of metabolites and digestive enzymes in carnivorous plants [32,34,[105][106][107]. It should be noted that the temporal dynamics of the systemic response are quite complex; in some cases, the systemic response clearly distinguishes between short-term and long-term phases of the response, such as for changes in photosynthesis activity [35,39,108,109], stomatal conductance [35,110,111] and ATP content [112]. However, despite the fact that the mechanisms of systemic response formation and the contribution of signals of different nature to the induction of each of the response phases remain poorly understood, the main features of this process can be distinguished.…”

“…The mechanisms of induction of a systemic response by an electrical signal can be analyzed using the example of the response of photosynthesis, as these responses are the most studied. The ES propagation causes a transient decrease in the activity of photosynthesis, manifested as a decrease in the rate of CO 2 assimilation [105,109,[113][114][115], and in changes in the parameters of the light reactions of photosynthesis-a decrease in the quantum yield of photosystem II, an increase in non-photochemical quenching (NPQ) [35,39,105,109,116]. The fast response phase, which usually proceeds no more than ten minutes, starts almost immediately after the occurrence of ES, and the lag period usually does not exceed several tens of seconds [108,113,114,116,117].…”

“…The fast response phase, which usually proceeds no more than ten minutes, starts almost immediately after the occurrence of ES, and the lag period usually does not exceed several tens of seconds [108,113,114,116,117]. A considerable role in the rapid decrease in the activity of photosynthesis belongs to the pH changes occurring during the generation of ES [109,113,114,118], which lead to the inactivation of the Calvin-Benson cycle [5,119], the increase in NPQ [120] and reduced availability of CO 2 for chloroplasts by changing the CO 2 :HCO 3 ratio [118,121] or activity of aquaporins [113].…”

Local action of moderate heating and illumination induces propagation of hyperpolarization electrical signals in wheat plants

“…System potential is a long-term hyperpolarization electrical signal (HES) (Zimmermann et al, 2009(Zimmermann et al, , 2016; i.e., signal with the initial hyperpolarization and following repolarization of the electrical potential across the plasma membrane. This electrical signal can be caused by actions of various stressors (including variation potential-inducing stressors; Lautner et al, 2005;Yudina et al, 2022); it is probably to be related to activation of the H + -ATP-ase in the plasma membrane (Zimmermann et al, 2009(Zimmermann et al, , 2016. Mechanisms of propagation of system potential are actively discussed (Zimmermann et al, 2009;Yudina et al, 2022).…”

“…This electrical signal can be caused by actions of various stressors (including variation potential-inducing stressors; Lautner et al, 2005;Yudina et al, 2022); it is probably to be related to activation of the H + -ATP-ase in the plasma membrane (Zimmermann et al, 2009(Zimmermann et al, , 2016. Mechanisms of propagation of system potential are actively discussed (Zimmermann et al, 2009;Yudina et al, 2022). Considering relations between generations of variation potential and system potential (Zimmermann et al, 2009), it cannot be excluded that system potential is also the local electrical response on propagation of the hydraulic wave (Yudina et al, 2022).…”